The Central Valley Regional Water Quality Control Board will consider adopting a plan next week to govern how farmers allow irrigation water to re-enter public waterways.

In September, the water board held four public-input sessions on a draft environmental document for its Irrigated Lands Regulatory Program. Staff responded to comments and produced a final version, allowing the board to consider adopting a plan at its April 7 meeting in Rancho Cordova.

The Southern San Joaquin Valley Water Quality Coalition said the document is "long, unclear, disjointed, repetitive and has its meaningful components totally camouflaged by voluminous content." In addition, the accompanying economic analysis has "significant flaws," the group said.

The Tulare County Farm Bureau said the outlined alternatives would "present additional increased and unnecessary regulatory burden on agricultural landowners and farm businesses."

The board has said management practices could foul the air, create noise pollution, and impact vegetation and wildlife. But submitted comments "did not result in determinations of any new significant environmental impacts," the board said.

The board has leeway to combine elements of the several alternatives that its staff has proposed. The staff estimated its preferred alternative would cost nearly $500 million to implement.

The effort to create long-term rules started in 2003, when a new law ended the agricultural waivers that for years had eased restrictions on the quality of farm runoff.

The waivers virtually exempted agriculture from fulfilling the discharge-quality requirements laid out by the Porter-Cologne Water Quality Control Act, a state law enacted in 1969.

The new law, passed by legislators in 1999, required the state's regional water boards to replace the waivers with waste-discharge requirements, or WDRs. To accomplish that, the Central Valley board enacted a conditional waiver requiring a study of the region's irrigation discharges. A second waiver enacted in 2006 expires next year.